EP0308982A2 - Convertisseur analogique-numérique à excellent rapport signal/bruit pour petits signaux - Google Patents

Convertisseur analogique-numérique à excellent rapport signal/bruit pour petits signaux Download PDF

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Publication number
EP0308982A2
EP0308982A2 EP88115804A EP88115804A EP0308982A2 EP 0308982 A2 EP0308982 A2 EP 0308982A2 EP 88115804 A EP88115804 A EP 88115804A EP 88115804 A EP88115804 A EP 88115804A EP 0308982 A2 EP0308982 A2 EP 0308982A2
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EP
European Patent Office
Prior art keywords
input
signal
output
analog
adder
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Granted
Application number
EP88115804A
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German (de)
English (en)
Other versions
EP0308982A3 (fr
EP0308982B1 (fr
Inventor
Akira C/O Nec Corporation Yukawa
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
NEC Corp
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NEC Corp
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Filing date
Publication date
Priority claimed from JP24214187A external-priority patent/JPS6484920A/ja
Priority claimed from JP24214287A external-priority patent/JPS6484921A/ja
Priority claimed from JP62249448A external-priority patent/JPH082021B2/ja
Application filed by NEC Corp filed Critical NEC Corp
Publication of EP0308982A2 publication Critical patent/EP0308982A2/fr
Publication of EP0308982A3 publication Critical patent/EP0308982A3/fr
Application granted granted Critical
Publication of EP0308982B1 publication Critical patent/EP0308982B1/fr
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

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    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/30—Delta-sigma modulation
    • H03M3/322—Continuously compensating for, or preventing, undesired influence of physical parameters
    • H03M3/324—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement
    • H03M3/326—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by averaging out the errors
    • H03M3/328—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by averaging out the errors using dither
    • H03M3/3287—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by averaging out the errors using dither the dither being at least partially dependent on the input signal
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/30—Delta-sigma modulation
    • H03M3/322—Continuously compensating for, or preventing, undesired influence of physical parameters
    • H03M3/324—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement
    • H03M3/326—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by averaging out the errors
    • H03M3/328—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by averaging out the errors using dither
    • H03M3/33—Continuously compensating for, or preventing, undesired influence of physical parameters characterised by means or methods for compensating or preventing more than one type of error at a time, e.g. by synchronisation or using a ratiometric arrangement by averaging out the errors using dither the dither being a random signal
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/30—Delta-sigma modulation
    • H03M3/39—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators
    • H03M3/412—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution
    • H03M3/422—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only
    • H03M3/43—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the number of quantisers and their type and resolution having one quantiser only the quantiser being a single bit one
    • H—ELECTRICITY
    • H03—ELECTRONIC CIRCUITRY
    • H03M—CODING; DECODING; CODE CONVERSION IN GENERAL
    • H03M3/00—Conversion of analogue values to or from differential modulation
    • H03M3/30—Delta-sigma modulation
    • H03M3/39—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators
    • H03M3/436—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the order of the loop filter, e.g. error feedback type
    • H03M3/456—Structural details of delta-sigma modulators, e.g. incremental delta-sigma modulators characterised by the order of the loop filter, e.g. error feedback type the modulator having a first order loop filter in the feedforward path

Definitions

  • the present invention relates to an analog-to-digital converter, and more specifically to an analog-to-digital converter for converting an input analog signal into a digital signal of a small bit number at a sampling rate which is considerably faster than the band of the input analog signal.
  • analog-to-digital converters of the type mentioned above there have been known a variety of types such as a delta-sigma modulator type, a delta modulator type, a first-order predicate primary noise shaping type, etc.
  • a typical delta-sigma modulator type analog-to-­digital converter includes an adder having an input connected to an analog signal input terminal and one integrator having an input connected to an output of the adder.
  • An output of the integrator is connected to a comparator or threshold detector which operates to convert a received analog signal into a digital signal at a given sampling frequency.
  • the digital signal is applied to a flipflop so that the digital signal is held for one period.
  • An output of the flipflop is inverted by an inverter and then supplied to a second input of the above mentioned adder so that a voltage corresponding to a difference between the analog signal of the input terminal and the one-period delayed output of the comparator is integrated by the integrator.
  • the first-order predicate primary noise shaping type analog-to-digital converter was proposed by Yukawa, A. et al in the International Conference on Acoustics, Speech, and Signal Processing in 1985.
  • This first-order predicate primary noise shaping type analog-to-digital converter and the delta-modulator type analog-to-digital converter are advantageous similarly to delta-sigma modulator type analog-to-digital converter, in that since the sampling frequency is very high and a spectral power density of the noise is distributed in a biased frequency range higher than the band of the signal. Therefore, even if the degree of resolution is lower than that of the conventional analog-­ to-digital converter, if it is evaluated in a band of the signal finally obtained, the in-band noise is low and a signal-to-­noise ratio is high.
  • the conventional analog-to-­digital converters are disadvantageous in that an excellent signal-to-noise ratio and input/output amplitude characteristics cannot be realized for a small signal
  • Another object of the present invention is to provide a analog-to-digital converter having a high signal-to-noise ratio and an excellent input/output amplitude characteristics even when a small signal is inputted.
  • an analog-to-digital converter which includes an analog-­to-digital converting circuit having at least an analog signal input terminal, an adder means having a first input connected to the analog signal input terminal and a second input, and a comparator having an input coupled to receive an output of the adder and operating to generate a digital signal at a given sampling frequency, this digital signal being applied to the second input of the adder means, wherein the improvement comprises a noise generator including an one-bit white noise generator connected to receive the digital signal outputted from the comparator for generating a one-bit white noise signal, and means coupled to the white noise generator for outputting a signal indicative of a difference between values of two white noise signals at two continuous sampling points, this difference signal being added to the input of the comparator.
  • the shown analog-­to-digital converter includes a delta-sigma modulator 10 having one analog integrator, similarly to a conventional delta-sigma modulator having one integrator.
  • the delta-­sigma modulator 10 includes an adder 12 having an input connected to an analog signal input terminal 14 and one analog integrator 16 having an input connected to an output of the adder 12.
  • An output of the integrator 16 is connected through another adder 18 to a threshold detector or comparator 20 which operates to convert a received analog signal into a digital signal at a given sampling rate or frequency.
  • the digital signal is fed to an output terminal 22 and also is applied to a D-type flipflop 24 so that the digital signal is held for one period of the sampling frequency.
  • An output of the flipflop 24 is coupled to an inverter 26 whose output is connected to a second input of the adder 12 so that a voltage corresponding to a difference between the analog signal of the input terminal 14 and the one-period delayed output of the comparator 20 is integrated by the integrator 16.
  • the shown analog-to-digital converter also includes a noise generator 30 which have a one-bit white noise generating circuit 32 connected at its input to the output of the comparator 20, and a D-type flipflop 34 connected to an output 33 of the one-bit white noise generating circuit 32 for generating a signal delayed by one sampling period.
  • the one-sampling period delayed signal is inputted to an inverter 36.
  • An output of the inverter 36 and the output 33 of the one-bit white noise generating circuit 32 are inputted to an adder 38 whose output is inputted to the adder 18 of the delta-sigma modulator 10.
  • the adder 38 generates a signal indicative of the difference between the outputs of the one-bit white noise generating circuit 32 at two succeeding sampling times.
  • the output signal of the adder 38 can assume three values, "0", "1” and "2". When one of these values is added to the output of the integrator 16 by the adder 18, the value of "0" corresponds to "-1", and "1" and “2" correspond to "0" and "1", respectively.
  • the magnitude of the signal added to the adder 18 is preferably one-fourth to one-­sixteenth of a voltage of the signal which is added for the output code "1" from the inverter 26 to the adder 12 so as to be fed back to the input analog signal of the input terminal 14
  • the one-bit white noise generating circuit 32 can be formed by various circuits. Referring to Figure 2, there is shown one typical white noise generating circuit which is called a "scrambler" and widely used in MODEMs.
  • the shown one-bit white noise generating circuit 32 includes a seven-stage shift register 40 in which outputs of sixth and seventh stages are connected to an exclusive-OR gate 42. An output of the exclusive-OR gate 42 is connected to one input of a second exclusive-OR gate 44 whose second input is connected to receive the output of the comparator 20. An output of the second exclusive-OR gate 44 is connected to an input of a first stage of the shift register 40, and forms the output 33 of the one-bit white noise generating circuit 32.
  • the delta-sigma modulator includes two integrators 16 and 16B which are cascade-coupled through an adder 12B.
  • the output of the inverter 26 is connected to nor only the adder 12 but also the adder 12B.
  • the magnitude of the signal added to the adder 18 is preferably one-fourth to one-sixteenth of a voltage of the signal which is added for the output code"1" from the inverter 26 to the adder 12 so as to be fed back to the input analog signal of the input terminal 14
  • the shown converter includes the first-order predicate primary noise shaping type analog-to-digital conversion circuit 50, similar to a conventional first-order predicate primary noise shaping type analog-to-digital converter.
  • the first-­order predicate primary noise shaping type analog-to­digital conversion circuit 50 includes an adder 52 having an input connected to an analog signal input terminal 54 and one analog integrator 56 having an input connected to an output of the adder 52.
  • An output of the integrator 56 is connected through another adder 58 to a threshold detector or comparator 70 which operates to convert a received signal into a digital signal at a given sampling rate or frequency, by discriminating whether the received signal is positive or negative.
  • the output of the comparator 60 is fed to a D-type flipflop 62 so that the digital signal is held for one period of the sampling frequency.
  • An output of the flipflop 62 is coupled to an inverter 64 whose output is connected to a prediction circuit 66.
  • This prediction circuit 66 includes an up-down counter 68 for example, and an input and an output of the prediction circuit 66 are digital-to-analog-converted and then applied to second and third inputs of the adder 52 so that the adder 52 outputs the difference between the signal from the input terminal 54 and the signals from the prediction circuit 66. Further, the output of the prediction circuit 66 is connected to an output terminal 70.
  • the shown analog-to-digital converter also includes a noise generator 30 similar to that shown in Figure 1. Namely, the output of the comparator 60 is connected to the input of the one-bit white noise generating circuit 32. In addition, the output of the adder 38 is connected to the adder 58. In this third embodiment, when the output of the adder 38 is inputted to the adder 58, the magnitude the signal added to the adder 58 is preferably one-half to one-eighth of a minimum resolution of the prediction circuit 66 for the output code "1".
  • the shown converter includes a delta modulator 80, similar to a conventional delta modulator.
  • the delta modulator 80 includes an adder 82 having a first input connected to an analog signal input terminal 84 and a threshold detector or comparator 86 having an input connected to an output of the adder 82.
  • This threshold detector or comparator 86 operates to convert a received signal into a digital signal at a given sampling rate or frequency, by discriminating whether the received signal is positive or negative.
  • the output of the comparator 86 is connected to an output terminal 88 and also fed to a D-type flipflop 90 so that the digital signal is held for one period of the sampling frequency.
  • An output of the flipflop 90 is coupled to a prediction circuit 92, whose output is connected to a second input of the adder 82.
  • the prediction circuit 92 can be formed of for example an up-down counter, similarly to the third embodiment shown in Figure 4. However, if the prediction circuit 92 is of the digital type, the output of the prediction circuit 92 is firstly digital-to-analog-converted and thereafter is inputted to the adder 82. As seen form the above, the adder 82 is primarily provided for the purpose of discriminating which of the input signal and the predicted signal is large. If the input signal is larger than the predicted signal, the prediction circuit 92 outputs a digital code "1", so that the predicted signal generated by the prediction circuit 92 is enlarged.
  • the shown analog-to-digital converter also includes a noise generator 30 similar to that shown in Figure 1. Namely, the output of the comparator 86 is connected to the input of the one-bit white noise generating circuit 32. In addition, the output of the adder 38 is connected to the adder 82. Also, in this fourth embodiment, when the output of the adder 38 is inputted to the adder 82, the magnitude of the signal added to the adder 82 is preferably one-half to one-eighth of a minimum resolution of the prediction circuit 92 for the output code "1".
  • the noise is positively added.
  • the meaning of the noise addition could be understood from evaluation of the power spectrum of the added noise.
  • the effective power of the amplitude of the newly added noise is D2
  • the sampling period is T
  • the angular frequency of the analog signal is ⁇
  • the output of the adder 38 can have the power spectrum expressed by D2 sin2 ( ⁇ T/2). Namely, a signal component of a low frequency is very small, and an out-of-band spectral component is large.
  • this spectrum is further converted into the distribution of D2 sin4 ( ⁇ T/2) in relation to the output signal in the case of the single integrator 16, and into a distribution of D2 sin6 ( ⁇ T/2) in the case of the two integrators 16A and 16B.
  • the inventor plans to locate a digital filter connected to the output terminal (22, 70, 88) of the analog-to-digital converter so that the out-of-band components are removed by the digital filter, with the result that only the in-band components can be obtained.

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  • Engineering & Computer Science (AREA)
  • Theoretical Computer Science (AREA)
  • Analogue/Digital Conversion (AREA)
  • Compression, Expansion, Code Conversion, And Decoders (AREA)
EP88115804A 1987-09-25 1988-09-26 Convertisseur analogique-numérique à excellent rapport signal/bruit pour petits signaux Expired - Lifetime EP0308982B1 (fr)

Applications Claiming Priority (6)

Application Number Priority Date Filing Date Title
JP242141/87 1987-09-25
JP24214187A JPS6484920A (en) 1987-09-25 1987-09-25 A/d converter
JP24214287A JPS6484921A (en) 1987-09-25 1987-09-25 A/d converter
JP242142/87 1987-09-25
JP62249448A JPH082021B2 (ja) 1987-10-01 1987-10-01 Ａ／ｄ変換器
JP249448/87 1987-10-01

Publications (3)

Publication Number Publication Date
EP0308982A2 true EP0308982A2 (fr) 1989-03-29
EP0308982A3 EP0308982A3 (fr) 1992-05-13
EP0308982B1 EP0308982B1 (fr) 1995-09-06

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EP88115804A Expired - Lifetime EP0308982B1 (fr) 1987-09-25 1988-09-26 Convertisseur analogique-numérique à excellent rapport signal/bruit pour petits signaux

Country Status (3)

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US (1) US5010347A (fr)
EP (1) EP0308982B1 (fr)
DE (1) DE3854414T2 (fr)

Cited By (6)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0419278A2 (fr) * 1989-09-21 1991-03-27 Xerox Corporation Convertisseur analogique-numérique
EP0515154A1 (fr) * 1991-05-21 1992-11-25 AT&T Corp. Suppression de la tonalité et du bruit périodique dans un canal au repos pour modulateurs sigma delta utilisant un signal de tremblement à haut niveau
FR2741471A1 (fr) * 1995-11-22 1997-05-23 Fujitsu Ltd Appareil et procede de demodulation de donnees, et appareil de lecture de donnees
WO2007040989A1 (fr) 2005-09-30 2007-04-12 Nxp B.V. Systeme et procede permettant d'ajuster la vibration dans un modulateur delta sigma
EP1193867B1 (fr) * 2000-09-22 2018-11-14 Texas Instruments Inc. Amplificateur numérique
US10659074B2 (en) 2016-12-14 2020-05-19 Sony Semiconductor Solutions Corporation Delta-sigma modulator, electronic device, and method for controlling delta-sigma modulator

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FI88980C (fi) * 1991-01-09 1993-07-26 Nokia Mobile Phones Ltd Sigma-delta-modulator foer d/a-omvandlare
US5274375A (en) * 1992-04-17 1993-12-28 Crystal Semiconductor Corporation Delta-sigma modulator for an analog-to-digital converter with low thermal noise performance
US5488368A (en) * 1993-05-28 1996-01-30 Technoview Inc. A/D converter system and method with temperature compensation
US5359327A (en) * 1993-05-28 1994-10-25 Brown Eric W A/D converter system with interface and passive voltage reference source
US5376892A (en) * 1993-07-26 1994-12-27 Texas Instruments Incorporated Sigma delta saturation detector and soft resetting circuit
US5909188A (en) * 1997-02-24 1999-06-01 Rosemont Inc. Process control transmitter with adaptive analog-to-digital converter
SE509408C2 (sv) 1997-05-27 1999-01-25 Ericsson Telefon Ab L M Anordning och förfarande för reducering av periodiskt brus i en sigma-delta modulator
US5905453A (en) * 1997-08-04 1999-05-18 Motorola, Inc. Dithered sigma delta modulator having programmable full scale range adjustment
US6448912B1 (en) * 1998-10-29 2002-09-10 Micron Technology, Inc. Oversampled centroid A to D converter
DE19851637A1 (de) * 1998-11-10 2000-05-11 Bosch Gmbh Robert Sigma-Delta-Modulator und Verfahren zur Unterdrückung eines Quantisierungsfehlers in einem Sigma-Delta-Modulator
US6215432B1 (en) 1999-03-04 2001-04-10 Atmel Corporation Reducing digital switching noise in mixed signal IC's
US6411242B1 (en) * 2000-06-13 2002-06-25 Linear Technology Corporation Oversampling analog-to-digital converter with improved DC offset performance
DE10142191C2 (de) * 2001-08-29 2003-08-28 Infineon Technologies Ag SD-ADC mit digitaler Dithersignalverarbeitung
US20040228545A1 (en) * 2003-05-12 2004-11-18 Kwang-Bo Cho Multisampling with reduced bit samples
US6927717B1 (en) 2004-02-12 2005-08-09 Linear Technology Corporation Buffered oversampling analog-to-digital converter with improved DC offset performance
US7224305B2 (en) * 2004-06-08 2007-05-29 Telefonaktiebolaget L M Ericsson (Publ) Analog-to-digital modulation
CN100440733C (zh) * 2005-12-31 2008-12-03 中国科学院声学研究所 一种对信号高效量化的模数转换器
WO2007144825A1 (fr) * 2006-06-15 2007-12-21 Koninklijke Philips Electronics N.V. Procédé d'équilibrage de consommation de puissance entre des charges
US7746257B2 (en) * 2008-05-07 2010-06-29 Cirrus Logic, Inc. Delta-sigma analog-to-digital converter circuit having reduced sampled reference noise
US8009077B1 (en) 2009-06-08 2011-08-30 Cirrus Logic, Inc. Delta-sigma analog-to-digital converter (ADC) circuit with selectively switched reference
CN102299874B (zh) * 2010-06-24 2014-03-12 大唐移动通信设备有限公司 一种获得链路增益的方法及装置
US8873611B2 (en) * 2010-09-10 2014-10-28 Nec Corporation Transmitter, control method, computer program and delta-sigma modulator
US8981982B2 (en) * 2013-04-05 2015-03-17 Maxlinear, Inc. Multi-zone data converters
CN103634005B (zh) * 2013-12-13 2017-06-06 戴祖渝 一种模数转换器中量化噪声随机化的方法
US9312875B1 (en) * 2015-06-26 2016-04-12 Intel IP Corporation Signal processing apparatus and method for processing a signal

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US4034367A (en) * 1974-02-28 1977-07-05 Yokogawa Electric Works, Ltd. Analog-to-digital converter utilizing a random noise source
WO1982004508A1 (fr) * 1981-06-12 1982-12-23 Inc Gould Codeur de modulation delta ameliore
EP0167412A2 (fr) * 1984-07-06 1986-01-08 British Aerospace Conversion analogique-numérique

Cited By (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
EP0419278A2 (fr) * 1989-09-21 1991-03-27 Xerox Corporation Convertisseur analogique-numérique
EP0419278A3 (en) * 1989-09-21 1991-08-21 Xerox Corporation Analogue-to-digital converters
US5099239A (en) * 1989-09-21 1992-03-24 Xerox Corporation Multi-channel analogue to digital convertor
EP0515154A1 (fr) * 1991-05-21 1992-11-25 AT&T Corp. Suppression de la tonalité et du bruit périodique dans un canal au repos pour modulateurs sigma delta utilisant un signal de tremblement à haut niveau
EP0709969A3 (fr) * 1991-05-21 1996-05-08 At & T Corp
FR2741471A1 (fr) * 1995-11-22 1997-05-23 Fujitsu Ltd Appareil et procede de demodulation de donnees, et appareil de lecture de donnees
NL1004585C2 (nl) * 1995-11-22 1999-11-24 Fujitsu Ltd Apparaat en werkwijze voor het demoduleren van datasignalen die uit een registratiemedium zijn gelezen.
EP1193867B1 (fr) * 2000-09-22 2018-11-14 Texas Instruments Inc. Amplificateur numérique
WO2007040989A1 (fr) 2005-09-30 2007-04-12 Nxp B.V. Systeme et procede permettant d'ajuster la vibration dans un modulateur delta sigma
US7224299B2 (en) 2005-09-30 2007-05-29 Nxp, B.V. System and method for adjusting dither in a delta sigma modulator
CN101273529B (zh) * 2005-09-30 2013-09-18 Nxp股份有限公司 用于Delta-Sigma调制器中调节抖动的系统及方法
US10659074B2 (en) 2016-12-14 2020-05-19 Sony Semiconductor Solutions Corporation Delta-sigma modulator, electronic device, and method for controlling delta-sigma modulator

Also Published As

Publication number Publication date
DE3854414T2 (de) 1996-04-18
EP0308982A3 (fr) 1992-05-13
DE3854414D1 (de) 1995-10-12
US5010347A (en) 1991-04-23
EP0308982B1 (fr) 1995-09-06

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